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Handling MPLS-TP OAM Packets Targeted at Internal MIPs. draft-farrel-mpls-tp-mip-mep-map-04 H. Endo , A. Farrel, Y. Koike, M. Paul, R. Winter. History. OAM framework specifies per-interface MIPs (two or more MIPs on each side of the forwarding engine)
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Handling MPLS-TP OAM Packets Targeted at Internal MIPs draft-farrel-mpls-tp-mip-mep-map-04 H. Endo , A. Farrel, Y. Koike, M. Paul, R. Winter
History • OAM framework specifies per-interface MIPs (two or more MIPs on each side of the forwarding engine) • Does not specify how OAM packets destined to per-interface MIPs are handled • Many possible options...needs to be specified for implementors
More history • Changes since -03 version • Removed the use of ACH TLVs based on feedback received • Removed the use of a reserved label based on feedback received • Described (two) new way(s) of addressing per interface MIPs • Merged with draft-koike-ietf-mpls-tp-oam-maintenance-points-01 • Appendix with ohter alternatives
Requirements • Forwarding of OAM packets exactly as data packets without mis-ordering. • Delivery of OAM messages to the correct MPLS-TP node. • Direction of OAM instructions to the correct MIP within an MPLS-TP node (arrival at the wrong MIP should be handled). • Packet inspection at the incoming and outgoing interfaces must be minimized.
Option 1 - Reserved bit • No semantic overlap with anything that exists • Still enough bits left (8 bits) • Potentially safe (must be ignored by legacy) • Hardware-friendly • Update to RFC 5586 and 4385, then works for both PWs and LSPs
0: ingress 1: egress 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLV Header (if present) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ Zero or more ACH TLVs ~ ~ (if present) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ G-ACh Message ~ ~ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option 2 – ID-based • Use existing ID information in the OAM messages • Leave it to the node implementation to deliver it • No „on-the-wire“ packet format changes required • Slightly more complex processing compared to option 1
ID TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Label | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | GAL | TC |S| TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 1|Version| Reserved | Channel Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ACH TLV Header (if present) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ Zero or more ACH TLVs ~ ~ (if present) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ~ ~ G-ACh Message ~ ~ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option 2 and current solutions • draft-on-demand-cv-05 already specifies Ingress/Egress IF_Num • Address/ID TLVs • Not a fixed location (within and across solutions) therefore a SW solution is needed • Need to make sure this solution is satisfying all of the requirements
Draft-on-demand-cv-05DSMAP/DDMAP address TLV 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MTU | Address Type | DS Flags | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ingress IF_Num (4 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Egress IF_Num (4 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Multipath Type| Depth Limit | Multipath Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Next steps • Come to a conclusion on which option to pick • Feedback please • Ensure this is safe in all conceivable cases (i.e. no OAM packet leakage) • WG adoption would be good • Even if it‘s just to get this requirement into the back of people‘s heads • would be standards track...or alternatively move the text into another document